CN114141539B - Preparation method of low-voltage electrode foil with good bending fatigue strength - Google Patents
Preparation method of low-voltage electrode foil with good bending fatigue strength Download PDFInfo
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- 239000011888 foil Substances 0.000 title claims abstract description 209
- 238000005452 bending Methods 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 186
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 172
- 238000000034 method Methods 0.000 claims abstract description 31
- 239000011247 coating layer Substances 0.000 claims abstract description 30
- 238000005260 corrosion Methods 0.000 claims abstract description 28
- 230000007797 corrosion Effects 0.000 claims abstract description 28
- 239000002002 slurry Substances 0.000 claims abstract description 24
- 239000002131 composite material Substances 0.000 claims abstract description 23
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 13
- 238000004140 cleaning Methods 0.000 claims abstract description 12
- 238000005097 cold rolling Methods 0.000 claims abstract description 11
- 238000001035 drying Methods 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 7
- 238000000576 coating method Methods 0.000 claims abstract description 6
- 239000011248 coating agent Substances 0.000 claims abstract description 5
- 238000007581 slurry coating method Methods 0.000 claims abstract description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 42
- 230000009471 action Effects 0.000 claims description 42
- 239000000243 solution Substances 0.000 claims description 34
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 28
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 28
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 21
- 239000002202 Polyethylene glycol Substances 0.000 claims description 15
- 229920001223 polyethylene glycol Polymers 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 15
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 14
- 239000011259 mixed solution Substances 0.000 claims description 14
- 235000006408 oxalic acid Nutrition 0.000 claims description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 238000000866 electrolytic etching Methods 0.000 claims description 12
- 238000002791 soaking Methods 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 7
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 7
- 229910017604 nitric acid Inorganic materials 0.000 claims description 7
- 239000008399 tap water Substances 0.000 claims description 7
- 235000020679 tap water Nutrition 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 6
- 238000005245 sintering Methods 0.000 claims description 3
- 239000001293 FEMA 3089 Substances 0.000 claims description 2
- 240000005561 Musa balbisiana Species 0.000 claims description 2
- 235000018290 Musa x paradisiaca Nutrition 0.000 claims description 2
- 239000003929 acidic solution Substances 0.000 claims description 2
- 239000000853 adhesive Substances 0.000 claims description 2
- 230000001070 adhesive effect Effects 0.000 claims description 2
- 239000011230 binding agent Substances 0.000 claims description 2
- 235000019441 ethanol Nutrition 0.000 claims description 2
- 239000003350 kerosene Substances 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- 239000012792 core layer Substances 0.000 abstract description 5
- 230000008859 change Effects 0.000 abstract description 3
- 230000006872 improvement Effects 0.000 description 13
- 239000010410 layer Substances 0.000 description 10
- 238000007598 dipping method Methods 0.000 description 5
- 238000005530 etching Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material
- H01G9/045—Electrodes or formation of dielectric layers thereon characterised by the material based on aluminium
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/13—Energy storage using capacitors
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
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Abstract
The invention relates to a preparation method of a low-voltage electrode foil with good bending fatigue strength, which comprises the following steps: performing oil removal operation on the first aluminum foil, the second aluminum foil and the third aluminum foil; sequentially carrying out operations of pre-electrolysis, electrolytic corrosion, cleaning and drying on the first aluminum foil; coating the aluminum-based slurry on a first aluminum foil to form primary slurry coating layers on the front surface and the back surface of the first aluminum foil; attaching the second aluminum foil and the third aluminum foil to the primary coating layer in a one-to-one correspondence manner to form a composite aluminum foil; performing cold rolling treatment on the composite aluminum foil; and heating and cooling the composite aluminum foil in sequence to obtain the product. In the actual manufacturing and forming process, the electrode foil used as the intermediate core layer is still fully corroded, so that the phenomenon that the capacitance of the low-voltage electrode foil is greatly reduced due to the change of a preparation process route is avoided. In addition, practical experimental data show that the low-voltage electrode foil prepared by the method has better bending fatigue strength on the premise that the overall thickness is kept unchanged.
Description
Technical Field
The invention relates to the technical field of electrode foil manufacturing, in particular to a preparation method of a low-voltage electrode foil with good bending fatigue strength.
Background
Electronic component products are increasingly required to have high capacity and small size. In practical manufacturing, on the premise that the electrode foil needs to have higher capacitance, it is also required to ensure that the electrode foil has good bending fatigue strength (the electrode foil inevitably needs to undergo multiple bending in the forming preparation and assembling processes) so as to avoid the phenomenon that the service life of the electrode foil is shortened due to the generation of bending cracks.
However, according to the previous manufacturing experience, the electrode foil is required to have a more sufficient surface etching to form etching holes with a deeper depth in order to increase the capacitance. For example, chinese invention patent 2021110678726 discloses a method for manufacturing an electrode foil for a solid aluminum electrolytic capacitor, comprising the steps of: immersing the aluminum foil in an acid solution; immersing the membrane in an acid solution again, and applying high-frequency pulse current to perform pre-electrolysis; sequentially performing first electrolytic etching and second electrolytic etching; repeating the first electrolytic etching and the second electrolytic etching at least three times; washing with pure water; cleaning with chemical cleaning liquid; washing with pure water again; and (4) performing high-temperature heat treatment and cooling. Through the cooperation of the early-stage acid etching treatment and the pre-electrolysis, the distribution uniformity of initial corrosion points formed on the surface of the aluminum foil can be effectively improved, the uniformity of subsequent electrolytic corrosion is greatly improved, and then a large-depth corrosion hole is formed on the surface of the electrode foil by means of an electrolytic corrosion process, so that the design goal of greatly improving the capacitance of the electrode foil is achieved.
However, it is known from the theoretical common knowledge that the capacitance and the bending fatigue strength of the electrode foil are a pair of contradictory parameters, that is, the bending fatigue strength is inevitably affected by the corrosion holes remaining on the surface of the electrode foil, and the bending fatigue strength is drastically reduced as the depth of the corrosion holes increases. Therefore, how to prepare an electrode foil having both high capacity characteristics and high bending fatigue strength characteristics is an urgent technical problem to be solved in the industry.
Disclosure of Invention
Therefore, in view of the above-mentioned problems and drawbacks, the present inventors have collected relevant information, evaluated and considered in many ways, and continuously conducted experiments and modifications by technicians with many years of research and development experience in this field, which finally resulted in the development of the method for preparing the low voltage electrode foil with good bending fatigue strength.
In order to solve the technical problem, the invention relates to a preparation method of a low-voltage electrode foil with good bending fatigue strength, which comprises the following steps:
s1, performing oil removal operation on a first aluminum foil, a second aluminum foil and a third aluminum foil;
s2, soaking the first aluminum foil obtained in the step S1 in an acid solution, and applying high-frequency pulse current to perform pre-electrolysis;
s3, performing electrolytic corrosion operation on the first aluminum foil obtained in the step S2;
s4, cleaning and drying the first aluminum foil obtained in the step S3;
s5, uniformly coating the aluminum-based slurry on the front surface and the back surface of the first aluminum foil obtained in the step S4, and then performing heating treatment until the aluminum-based slurry is completely cured and sintered so as to form a primary slurry coating layer on the front surface and the back surface of the first aluminum foil;
s6, attaching the second aluminum foil and the third aluminum foil to the primary coating layer obtained in the step S5 in a one-to-one correspondence mode to form a composite aluminum foil;
s7, performing cold rolling treatment on the composite aluminum foil obtained in the step S6;
s8, placing the composite aluminum foil obtained in the step S7 in an oven to perform high-temperature heat treatment operation;
and S9, cooling the composite aluminum foil obtained in the step S8 to obtain the product.
As a further improvement of the technical solution disclosed in the present invention, in step S5, the aluminum-based slurry is preferably formed by mixing and stirring aluminum powder and a binder.
As a further improvement of the technical scheme disclosed by the invention, the adhesive is preferably formed by mixing polyethylene glycol and absolute ethyl alcohol.
As a further improvement of the technical scheme disclosed by the invention, the average particle diameter D50 of the aluminum powder is preferably controlled to be 2-5 μm, and the average molecular weight of the polyethylene glycol is preferably controlled to be 300-800.
As a further improvement of the technical scheme disclosed by the invention, in step S5, the first aluminum foil after being coated with the paste is placed in an oven for heating, and the baking conditions are as follows: the temperature is 300-500 ℃ and the time is 60-180 s.
As a further improvement of the technical solution disclosed in the present invention, step S5 includes a substep S51, after the primary coating layer is formed, step S51 is used to uniformly coat the aluminum-based slurry on the primary coating layer again, and then temperature-raising curing and sintering processes are performed to form secondary coating layers on both the front and back surfaces of the first aluminum foil.
As a further improvement of the technical solution disclosed in the present invention, in step S6, before the second aluminum foil and the third aluminum foil are attached to the front surface and the back surface of the first aluminum foil obtained in step S5, pre-electrolysis and electrolytic etching operations are sequentially performed on the second aluminum foil and the third aluminum foil.
As a further improvement of the technical scheme disclosed by the invention, in step S1, the first aluminum foil, the second aluminum foil and the third aluminum foil are immersed in a sodium hydroxide solution with a mass percentage concentration of 0.1-0.5%, and the action conditions are as follows: the temperature is 30-60 ℃, and the time is 60-180 s.
As another modification of the above technical solution, in step S1, the first aluminum foil, the second aluminum foil, and the third aluminum foil may be immersed in an organic solution. The organic solution is preferably any one of banana oil, turpentine oil, alcohol, gasoline and kerosene.
As a further improvement of the technical scheme disclosed by the invention, in the step S2, the used acidic solution is a phosphoric acid solution with a mass percentage concentration of 0.1-0.5%, and the action conditions are as follows: the temperature is 20-50 ℃, and the time is 30-120 s; the frequency of the high-frequency pulse current is controlled to be 10-20 KHz.
As a further improvement of the technical scheme disclosed by the invention, in step S3, the first aluminum foil obtained in step S2 is placed in a mixed solution of hydrochloric acid, sulfuric acid and oxalic acid for primary electrolytic corrosion, and the action conditions are as follows: the temperature is 30-60 ℃, the current is sine wave alternating current, the frequency is 40-70 Hz, and the time is 60-200 s; and then, continuously placing the first aluminum foil in a mixed solution of hydrochloric acid, sulfuric acid and oxalic acid for secondary electrolytic corrosion, wherein the action conditions are as follows: the temperature is 30-60 ℃, the current is square wave alternating current, the frequency is 40-70 Hz, and the time is 100-400 s.
As a further improvement of the technical proposal disclosed by the invention, in the step S3, the repetition times of the primary electrolytic corrosion and the secondary electrolytic corrosion are not less than 2.
As a further improvement of the technical scheme disclosed by the invention, in step S4, the first aluminum foil obtained in step S3 is placed in tap water for washing for 100-200S; then placing the mixture into a nitric acid solution with the mass percentage concentration of 2-8% for cleaning, wherein the action conditions are as follows: the temperature is 40-80 ℃, and the time is 100-300 s; then placing the mixture in pure water again for washing for 300-600 s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 85-100 ℃, and the time is 40-60 s.
As a further improvement of the technical solution disclosed in the present invention, in step S8, the working conditions of the oven are: the temperature is controlled to be 300-500 ℃, and the time is controlled to be 60-180 s.
As a further improvement of the technical scheme disclosed by the invention, the thickness of the first aluminum foil is controlled to be 80-100 mu m; and the thickness of the second aluminum foil and the third aluminum foil is controlled to be 5-10 mu m.
Compared with the traditional manufacturing method of the low-voltage electrode foil, in the technical scheme disclosed by the invention, the manufactured low-voltage electrode foil has five different functional partitions, and the manufactured low-voltage electrode foil is observed along the thickness direction of the low-voltage electrode foil and sequentially comprises a surface foil layer, a sintered layer, an electrode foil middle core layer, a sintered layer and a light foil layer. In the actual manufacturing and forming process, the electrode foil used as the middle core layer is still fully corroded, so that the phenomenon that the capacitance of the low-voltage electrode foil is greatly reduced due to the change of a forming process is effectively avoided. More importantly, practical experimental data show that on the premise that the whole thickness is unchanged, the layered structure has better bending fatigue strength compared with an integrated structure, and further the phenomenon that cracks appear in advance due to repeated bending in the process of forming preparation or assembling is avoided.
Detailed Description
For the purpose of enhancing understanding of the present invention, the present invention will be further described in detail with reference to the following examples, which are provided for illustration only and are not to be construed as limiting the scope of the present invention. The methods are conventional methods, not specifically described.
Example 1
S1, soaking a first aluminum foil, a second aluminum foil and a third aluminum foil which have the purity of 99.98% and the thickness of 100 mu m in 0.5wt% of sodium hydroxide solution, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 60s;
s2, soaking the first aluminum foil obtained in the step S1 in 0.25wt% of phosphoric acid solution, and applying high-frequency pulse current for pre-electrolysis under the action conditions: the temperature is 40 ℃, the time is 40s, and the frequency is 14KHz;
s3, placing the first aluminum foil obtained in the step S2 in a mixed solution of 9.0wt% hydrochloric acid, 1.0wt% sulfuric acid and 1.0wt% oxalic acid for first electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is sine wave alternating current, the current density is 0.9A/cm, the frequency is 45Hz, and the time is 90s; then placing the mixture into a mixed solution of 8.0wt% hydrochloric acid, 0.9wt% sulfuric acid and 1.0wt% oxalic acid to carry out second electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is square wave alternating current, the current density is 0.5A/cm, the frequency is 55Hz, and the time is 65s;
remarking: through the cooperation of the early-stage acid etching treatment and the pre-electrolysis, the distribution uniformity of initial corrosion points formed on the surface of the aluminum foil can be effectively improved, the uniformity of subsequent electrolytic corrosion is greatly improved, and the consistency of the capacity of the electrode foil is finally improved.
S4, placing the first aluminum foil obtained in the step S3 in tap water for washing for 120S; then placing the mixture in 5wt% nitric acid solution for cleaning, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 120s; placing in pure water again for washing for 360s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 95 ℃ and the time is 60s;
s5, dipping the first aluminum foil obtained in the step S4 in the aluminum-based slurry to form coating layers on two sides of the first aluminum foil, and then baking the first aluminum foil for 5 minutes through a baking oven at the temperature of 350 ℃ to sinter and form a primary coating layer on the front side and the back side of the first aluminum foil;
in the step, the aluminum-based slurry is prepared by uniformly mixing aluminum powder, polyethylene glycol and absolute ethyl alcohol, and the mass ratio of the aluminum powder to the polyethylene glycol to the absolute ethyl alcohol is 15:2:1. the average grain diameter D50 of the aluminum powder is controlled to be 2-5 mu m, and the average molecular weight of the polyethylene glycol is controlled to be 400;
s6, attaching a second aluminum foil and a third aluminum foil with the purity of 99.98% and the thickness of 10 microns to the primary coating layer obtained in the step S5 in a one-to-one correspondence mode to form a composite aluminum foil;
s7, performing cold rolling treatment on the composite aluminum foil obtained in the step S6, wherein the cold rolling feeding speed is controlled at 80m/h, and the pressure is controlled below 15 Mpa;
s8, placing the composite aluminum foil obtained in the step S7 in an oven to perform high-temperature heat treatment operation; the working conditions of the oven are as follows: the temperature is controlled at 350 ℃ and the time is controlled at 90s.
And S9, cooling the composite aluminum foil obtained in the step S8 to obtain the product.
Example 2
S1, soaking a first aluminum foil with the purity of 99.98 percent and the thickness of 100 mu m, a second aluminum foil with the purity of 99.98 percent and the thickness of 10 mu m and a third aluminum foil in 0.5wt percent of sodium hydroxide solution, and performing the following steps: the temperature is 50 ℃ and the time is 60s;
s2, soaking the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S1 in 0.25wt% of phosphoric acid solution, and applying high-frequency pulse current for pre-electrolysis under the action conditions: the temperature is 40 ℃, the time is 40s, and the frequency is 14KHz;
s3, placing the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S2 in a mixed solution of 9.0wt% hydrochloric acid, 1.0wt% sulfuric acid and 1.0wt% oxalic acid for first electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is sine wave alternating current, the current density is 0.9A/cm, the frequency is 45Hz, and the time is 90s; then placing the mixture into a mixed solution of 8.0wt% hydrochloric acid, 0.9wt% sulfuric acid and 1.0wt% oxalic acid to carry out second electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is square wave alternating current, the current density is 0.5A/cm, the frequency is 55Hz, and the time is 65s;
s4, placing the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S3 in tap water for washing for 120S; then placing the mixture in 5wt% nitric acid solution for cleaning, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 120s; placing in pure water again for washing for 360s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 95 ℃ and the time is 60s;
s5, dipping the first aluminum foil obtained in the step S4 in the aluminum-based slurry to form coating layers on two sides of the first aluminum foil, and then baking the first aluminum foil for 5 minutes through a baking oven at the temperature of 350 ℃ to sinter and form a primary coating layer on the front side and the back side of the first aluminum foil;
in the step, the aluminum-based slurry is prepared by uniformly mixing aluminum powder, polyethylene glycol and absolute ethyl alcohol, wherein the mass ratio of the aluminum powder to the polyethylene glycol to the absolute ethyl alcohol is 15:2:1. the average grain diameter D50 of the aluminum powder is controlled to be 2-5 mu m, and the average molecular weight of the polyethylene glycol is controlled to be 400;
s6, attaching the second aluminum foil and the third aluminum foil obtained in the step S4 to the primary coating layer obtained in the step S5 in a one-to-one correspondence mode to form a composite aluminum foil;
s7, performing cold rolling treatment on the composite aluminum foil obtained in the step S6, wherein the cold rolling feeding speed is controlled to be 80m/h, and the pressure is controlled to be below 15 Mpa;
s8, placing the composite aluminum foil obtained in the step S7 in an oven to perform high-temperature heat treatment operation; the working conditions of the oven are as follows: the temperature is controlled at 350 ℃ and the time is controlled at 90s.
And S9, cooling the composite aluminum foil obtained in the step S8 to obtain the product.
The main differences between example 2 and example 1 are: the second aluminum foil and the third aluminum foil are also subjected to pre-electrolysis and electrolytic corrosion treatment, so that the electric capacity of the prepared low-voltage electrode foil is well paved, but the bending fatigue strength of the low-voltage electrode foil is slightly reduced.
Example 3
S1, soaking a first aluminum foil with the purity of 99.98 percent and the thickness of 100 microns, a second aluminum foil with the purity of 99.98 percent and the thickness of 10 microns and a third aluminum foil in 0.5 weight percent of sodium hydroxide solution, and performing the following steps: the temperature is 50 ℃ and the time is 60s;
s2, soaking the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S1 in 0.25wt% of phosphoric acid solution, and applying high-frequency pulse current for pre-electrolysis under the action conditions: the temperature is 40 ℃, the time is 40s, and the frequency is 14KHz;
s3, placing the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S2 in a mixed solution of 9.0wt% hydrochloric acid, 1.0wt% sulfuric acid and 1.0wt% oxalic acid for first electrolytic corrosion, wherein the action conditions are as follows: temperature 50 ℃, current is sine wave alternating current, current density is 0.9A/cm, frequency is 45Hz, time is 90s; then placing the mixture into a mixed solution of 8.0wt% hydrochloric acid, 0.9wt% sulfuric acid and 1.0wt% oxalic acid for second electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is square wave alternating current, the current density is 0.5A/cm, the frequency is 55Hz, and the time is 65s;
s4, placing the first aluminum foil, the second aluminum foil and the third aluminum foil obtained in the step S3 in tap water for washing for 120S; then placing the mixture in 5wt% nitric acid solution for cleaning, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 120s; placing in pure water again for washing for 360s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 95 ℃ and the time is 60s;
s5, dipping the first aluminum foil obtained in the step S4 in aluminum-based slurry to form coating layers on two sides of the aluminum-based slurry, and then baking the aluminum-based slurry for 5 minutes by using an oven with the temperature of 350 ℃ to sinter and form a primary coating layer on the front side and the back side of the first aluminum foil;
in the step, the aluminum-based slurry is prepared by uniformly mixing aluminum powder, polyethylene glycol and absolute ethyl alcohol, wherein the mass ratio of the aluminum powder to the polyethylene glycol to the absolute ethyl alcohol is 15:2:1. the average grain diameter D50 of the aluminum powder is controlled to be 2-5 mu m, and the average molecular weight of the polyethylene glycol is controlled to be 400;
s6, continuously coating the aluminum-based slurry on the outer surface of the primary coating layer, and baking for 5 minutes through a baking oven at the temperature of 350 ℃ to sinter and form a secondary coating layer on the outer surface of the primary coating layer;
s7, respectively attaching the second aluminum foil and the third aluminum foil obtained in the step S4 to the secondary coating layer obtained in the step S6 in a one-to-one correspondence manner to form a composite aluminum foil;
s8, performing cold rolling treatment on the composite aluminum foil obtained in the step S7, wherein the cold rolling feeding speed is controlled at 80m/h, and the pressure is controlled below 15 Mpa;
s9, placing the composite aluminum foil obtained in the step S8 in an oven to perform high-temperature heat treatment operation; the working conditions of the oven are as follows: the temperature is controlled at 350 ℃ and the time is controlled at 90s.
And S10, cooling the composite aluminum foil obtained in the step S9 to obtain a product.
The main differences between example 3 and example 2 are: the thickness of the aluminum-based slurry layer is increased (due to the addition of the secondary coating layer). It is known that, during the course of the elevated-temperature sintering of an aluminum-based slurry, a large number of cavities are formed therein by the heat. Therefore, as the thickness of the aluminum-based slurry layer increases, the prepared and molded low-voltage electrode foil has higher capacitance, but the bonding strength of the second electrode foil, the third electrode foil and the first electrode foil is influenced to a certain extent, and the bending fatigue strength is reduced to a small extent.
The manufactured low-voltage electrode foil has five different functional subareas, and the manufactured low-voltage electrode foil is observed along the thickness direction of the low-voltage electrode foil and sequentially comprises a surface foil layer, a sintered layer, an electrode foil middle core layer, the sintered layer and a light foil layer. In the actual manufacturing and forming process, the electrode foil used as the middle core layer is still fully corroded, so that the phenomenon that the capacitance of the low-voltage electrode foil is greatly reduced due to the change of a forming process is effectively avoided. More importantly, practical experimental data show that on the premise that the whole thickness is kept unchanged, the layered structure has better bending fatigue strength compared with an integrated structure, and further the phenomenon that cracks appear in advance due to repeated bending in the forming preparation process or the assembling process is avoided.
The following points also need to be explained here:
1) The aluminum-based slurry is preferably prepared by uniformly mixing aluminum powder, polyethylene glycol and absolute ethyl alcohol. The polyethylene glycol and the absolute ethyl alcohol have good fluidity and relatively small molecular weight, so that the aluminum-based slurry is ensured to have excellent fluidity in the coating process, the integral uniformity of a primary coating layer and a secondary coating layer after forming is ensured, and the thickness of each area is consistent;
2) The aluminum-based slurry is coated on the first aluminum foil or the primary coating layer preferably by adopting a dipping method, so that the method is suitable for industrial continuous production requirements. In addition, the thickness of the coating layer can be adjusted through multiple times of dipping, so that different specific volumes of products can be obtained;
3) The second aluminum foil and the third aluminum foil are fixed with the first aluminum foil into a whole in a cold rolling mode, so that on one hand, the phenomenon that a primary coating layer and a secondary coating layer sintered on the surface of the first aluminum foil are peeled off due to the action of external force can be effectively prevented in the actual preparation and forming process and the actual application; on the other hand, the cold rolling treatment mode can also improve the overall tensile ductility of the low-voltage electrode foil to a certain extent, and the phenomenon that the low-voltage electrode foil is pulled to be cracked due to the action of tensile force in the subsequent winding process is avoided;
in order to more intuitively show the beneficial effects generated by the technical scheme of the invention, the following two groups of comparison tests are also provided, specifically:
comparative test 1:
1. an aluminum foil with the purity of 99.98 percent and the thickness of 100 mu m is soaked in a 0.5 weight percent sodium hydroxide solution, and the action conditions are as follows: the temperature is 50 ℃ and the time is 60S, and S1 is obtained;
2. soaking S1 in 0.25wt% phosphoric acid solution, applying high-frequency pulse current for pre-electrolysis, and performing action conditions as follows: obtaining S2 at the temperature of 40 ℃, the time of 60S and the frequency of 14KHz;
3. placing the S2 in a mixed solution of 9.0wt% hydrochloric acid, 1.0wt% sulfuric acid and 1.0wt% oxalic acid for first electrolytic corrosion, wherein the action conditions are as follows: temperature 50 ℃, current is sine wave alternating current, current density is 1.0A/cm, frequency is 45Hz, time is 100s; then placing the mixture into a mixed solution of 8.0wt% hydrochloric acid, 0.9wt% sulfuric acid and 1.0wt% oxalic acid to carry out second electrolytic corrosion, wherein the action conditions are as follows: the temperature is 50 ℃, the current is square wave alternating current, the current density is 0.6A/cm, the frequency is 55Hz, and the time is 60s; repeating the first electrolytic etching and the second electrolytic etching for five times to obtain S3;
4. putting the S3 into tap water for washing for 120S; then placing the mixture in 5wt% nitric acid solution for cleaning, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 120s; placing in pure water again for washing for 360s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 95 ℃ and the time is 60s; and obtaining a finished product.
Comparative experiment 2:
1. an aluminum foil with the purity of 99.98 percent and the thickness of 100 mu m is soaked in a 0.5 weight percent sodium hydroxide solution, and the action conditions are as follows: the temperature is 50 ℃ and the time is 60S, and S1 is obtained;
2. soaking S1 in 0.25wt% phosphoric acid solution, applying high-frequency pulse current for pre-electrolysis, and performing action conditions as follows: obtaining S2 at the temperature of 40 ℃, the time of 40S and the frequency of 14KHz;
3. placing S2 in a mixed solution of 9.0wt% hydrochloric acid, 1.0wt% sulfuric acid and 1.0wt% oxalic acid for first electrolytic corrosion, wherein the action conditions are as follows: temperature 50 ℃, current is sine wave alternating current, current density is 0.9A/cm, frequency is 45Hz, time is 90s; then placing the mixture into a mixed solution of 8.0wt% hydrochloric acid, 0.9wt% sulfuric acid and 1.0wt% oxalic acid to carry out second electrolytic corrosion, wherein the action conditions are as follows: temperature 50 ℃, current is square wave alternating current, current density is 0.5A/cm, frequency is 55Hz, time is 65s; repeating the first electrolytic etching and the second electrolytic etching for five times to obtain S3;
4. putting the S3 into tap water for washing for 120S; then placing the mixture in 5wt% nitric acid solution for cleaning, wherein the action conditions are as follows: the temperature is 50 ℃ and the time is 120s; placing in pure water again for washing for 360s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 95 ℃ and the time is 60s; and obtaining a finished product.
Table 1 shows the results of the specific volume and the number of times of bending resistance of the low voltage electrode foil obtained in examples 1 to 3 and comparative experiments 1 to 2
TABLE 1
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (15)
1. The preparation method of the low-voltage electrode foil with good bending fatigue strength is characterized by comprising the following steps:
s1, performing oil removal operation on a first aluminum foil, a second aluminum foil and a third aluminum foil;
s2, soaking the first aluminum foil obtained in the step S1 in an acid solution, and applying high-frequency pulse current for pre-electrolysis;
s3, performing electrolytic corrosion operation on the first aluminum foil obtained in the step S2;
s4, cleaning and drying the first aluminum foil obtained in the step S3;
s5, uniformly coating the aluminum-based slurry on the front surface and the back surface of the first aluminum foil obtained in the step S4, and then performing heating treatment until the aluminum-based slurry is completely cured and sintered so as to form primary slurry coating layers on the front surface and the back surface of the first aluminum foil;
s6, attaching the second aluminum foil and the third aluminum foil to the primary coating obtained in the step S5 in a one-to-one correspondence mode to form a composite aluminum foil;
s7, performing cold rolling treatment on the composite aluminum foil obtained in the step S6;
s8, placing the composite aluminum foil obtained in the step S7 in an oven to perform high-temperature heat treatment operation;
and S9, cooling the composite aluminum foil obtained in the step S8 to obtain the product.
2. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein in step S5, the aluminum-based slurry is prepared by mixing and stirring aluminum powder and a binder.
3. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 2, wherein the adhesive is formed by mixing polyethylene glycol and absolute ethyl alcohol.
4. The method for preparing a low-voltage electrode foil with good bending fatigue strength according to claim 3, wherein the average particle diameter D50 of the aluminum powder is controlled to be 2-5 μm, and the average molecular weight of the polyethylene glycol is controlled to be 300-800.
5. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein in step S5, the first aluminum foil after being coated with the paste is placed in an oven to be heated, and the baking conditions are as follows: the temperature is 300-500 ℃ and the time is 60-180 s.
6. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein the step S5 comprises the substep of S51; after the primary coating layer is formed, step S51 is performed to uniformly coat the aluminum-based slurry on the primary coating layer again, and then, temperature-raising curing and sintering processes are performed to form a secondary coating layer on both the front and back surfaces of the first aluminum foil.
7. The method as claimed in claim 1, wherein in step S6, pre-electrolysis and electrolytic etching are sequentially performed on the second aluminum foil and the third aluminum foil before the second aluminum foil and the third aluminum foil are attached to the front surface and the back surface of the first aluminum foil obtained in step S5.
8. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein in step S1, the first aluminum foil, the second aluminum foil and the third aluminum foil are all immersed in a sodium hydroxide solution with a mass percent concentration of 0.1-0.5%, and the action conditions are as follows: the temperature is 30-60 ℃, and the time is 60-180 s.
9. The method for manufacturing a low-voltage electrode foil with good bending fatigue strength according to claim 1, wherein in step S1, the first aluminum foil, the second aluminum foil, and the third aluminum foil are immersed in an organic solution; the organic solution is any one of banana oil, turpentine oil, alcohol, gasoline and kerosene.
10. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein in step S2, the acidic solution is a phosphoric acid solution with a mass percentage concentration of 0.1-0.5%, and the action conditions are as follows: the temperature is 20-50 ℃, and the time is 30-120 s; the frequency of the high-frequency pulse current is controlled to be 10-20 KHz.
11. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein in step S3, the first aluminum foil obtained in step S2 is placed in a mixed solution of hydrochloric acid, sulfuric acid and oxalic acid for electrolytic corrosion for one time, and the action conditions are as follows: the temperature is 30-60 ℃, the current is sine wave alternating current, the frequency is 40-70 Hz, and the time is 60-200 s; and then continuously placing the first aluminum foil in a mixed solution of hydrochloric acid, sulfuric acid and oxalic acid for secondary electrolytic corrosion, wherein the action conditions are as follows: the temperature is 30-60 ℃, the current is square wave alternating current, the frequency is 40-70 Hz, and the time is 100-400 s.
12. The method for producing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 11, wherein in step S3, the number of repetitions of the primary electrolytic etching and the secondary electrolytic etching is not less than 2.
13. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 12, wherein in step S4, the first aluminum foil obtained in step S3 is washed in tap water for 100 to 200 seconds; then placing the mixture into a nitric acid solution with the mass percentage concentration of 2-8% for cleaning, wherein the action conditions are as follows: the temperature is 40-80 ℃, and the time is 100-300 s; then placing the mixture in pure water again for washing for 300-600 s; finally, placing the mixture in a drying oven, wherein the action conditions are as follows: the temperature is 85-100 ℃ and the time is 40-60 s.
14. The method for preparing a low-voltage electrode foil with good bending fatigue strength according to claim 1, wherein in step S8, the operating conditions of the oven are as follows: the temperature is controlled to be 300-500 ℃, and the time is controlled to be 60-180 s.
15. The method for preparing a low-voltage electrode foil with good bending fatigue strength as claimed in claim 1, wherein the thickness of the first aluminum foil is controlled to be 80-100 μm; and the thickness of the second aluminum foil and the third aluminum foil is controlled to be 5-10 mu m.
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| PCT/CN2022/077207 WO2023103181A1 (en) | 2021-12-08 | 2022-02-22 | Preparation method for low-voltage electrode foil having good bending fatigue strength |
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| CN108172321A (en) * | 2017-12-19 | 2018-06-15 | 宇东箔材科技南通有限公司 | A kind of solid capacitor carbon foil and preparation method thereof |
| CN110517892A (en) * | 2019-09-18 | 2019-11-29 | 南通海星电子股份有限公司 | A kind of manufacturing method of solid-state aluminum electrolytic capacitor electrode foil |
| CN113502476A (en) * | 2021-09-13 | 2021-10-15 | 南通海星电子股份有限公司 | Method for manufacturing electrode foil for solid aluminum electrolytic capacitor |
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| EP1233432B1 (en) * | 2001-02-14 | 2011-12-14 | Panasonic Corporation | Electrode foil for aluminum electrolytic capacitor and method of manufacturing the same |
| US6459565B1 (en) * | 2001-06-11 | 2002-10-01 | Kemet Electronics Corporation | Surface mount aluminum capacitor having anode foil anodized in an aqueous phosphate solution |
| JP4572649B2 (en) * | 2004-10-12 | 2010-11-04 | パナソニック株式会社 | Method for producing electrode foil for electrolytic capacitor |
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| CN108172321A (en) * | 2017-12-19 | 2018-06-15 | 宇东箔材科技南通有限公司 | A kind of solid capacitor carbon foil and preparation method thereof |
| CN110517892A (en) * | 2019-09-18 | 2019-11-29 | 南通海星电子股份有限公司 | A kind of manufacturing method of solid-state aluminum electrolytic capacitor electrode foil |
| CN113502476A (en) * | 2021-09-13 | 2021-10-15 | 南通海星电子股份有限公司 | Method for manufacturing electrode foil for solid aluminum electrolytic capacitor |
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